Please help! trying to find the name of a movie
 

Hi there.
I wonder if you can help me please. I have been wracking my brains for the last few years trying to remember the title of an old B&W Japanese movie that I saw years ago on TV.

The movie was set in feudal Japan and is centred around an aging warlord who had managed to build up a mighty clan over his lifetime. His only regret was that he’d never managed to conquer the neighbouring clans because they were too powerful and had highly defended fortresses. He decided to retire which his rivals saw as weakness, so they immediately invaded and humiliated the aging warlord. After this they began fighting amongst themselves with one eventual winner who after battling and having suffered mighty losses now controls all of the local territories.
Just when we thought everything was done and dusted, the aging warlord turns up again and flips things and seizes control of everything. It seems that the aging war lord wasn’t as toothless and weak as the others had though and this was all his ploy to lure his enemies out of their strongholds and let them weaken themselves by fighting each other for control of the region. He now controls all of the entire region and clans and fulfils his lifes ambition.

This was a truly great movie with good acting, great script and a masterful plot that I would dearly love to see again. Does anyone know this movie and can please tell me the title?

Many thanks in advance.